Group Title: Animal Science Department mimeograph series - Florida Agricultural Experiment Station ; AN67-5
Title: Chemical composition and rumen metabolism of a cattle diet in different physical forms
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Title: Chemical composition and rumen metabolism of a cattle diet in different physical forms
Series Title: Animal Science Department mimeograph series
Physical Description: 13 p. : ill. ; 28 cm.
Language: English
Creator: Hentges, J. F ( James Franklin ), 1925-
University of Florida -- Dept. of Animal Science
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1966
 Subjects
Subject: Cattle -- Feeding and feeds -- Florida   ( lcsh )
Feeds -- Microbiology -- Florida   ( lcsh )
Ruminants -- Feeding and feeds -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 6-8).
Statement of Responsibility: J.F. Hentges, Jr. ... et al..
General Note: Caption title.
General Note: "October, 1966."
Funding: Department of Animal Science mimeograph series ;
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Bibliographic ID: UF00072983
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 78595603

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Animal Science Department DEC 2 1966 Florida Agricultural
Mimeograph Series AN67-5 Experiment Station
October, 1966 Gainesville, Florida
I.F.A.S. Univ. of Florida
CHEMICAL CO MS TTON Ann TM MUAMT M OF A
CATTLE DIET IN DIFFERENT'PHYSICAL FORMS

J. F. Hentges, Jr., M. T. Cabezas, J. E. Moore Pnd C. J. Wilcox
Florida Agricultural Experiment Station, Gainesville

Previous experiments showed that steers fed either a diet containing flaked corn
or a pelleted diet containing corn meal gained slightly faster and with more efficient
utilization of feed than steers fed a diet.containing ground corn (Cabezas et al.,
1964). The better utilization of flaked corn and pelleted corn diets was attributed
to changes in physical and chemical characteristics which may have caused a different
type of rumen fermentation. According to Armstrong and Blaxter (1957a,b) and Armstrong
et al. (1958), the amounts and proportions of volatile fatty acids (VFA) produced dur-
ing fermentation of feed by rumen microorganisms play an important role in the energy
metabolism of sheep.

The objective of this study was to determine whether alteration of the physical
and chemical characteristics of corn by flaking and pelleting would have an effect on
levels of ruminal VFA and soluble carbohydrates when compared to a similar non-pelleted
diet containing ground corn.


Experimental Procedure

Six yearling Angus steers fitted with permanent fistulae were randomly assigned
to dietary treatments in two Latin Square groups with three treatments and three per-
iods. Each treatment period was four weeks in length during which the.steers were fed
the diets presented in Table 1.

The diets were identical in ingredient composition but differed in physical form.
Dietary treatments were a diet containing hammermill ground corn (HGC), the HGC-diet
pelleted through a 1/4 in. die (HGC-P) and a diet containing flaked or steamed rolled
cracked corn (SRC).

The steers were kept in concrete-floored pens and were individually fed once
daily at 3:00 a.m. During each of the first 10 days of each period, increasing amounts
of feed were offered to determine the voluntary feed consumption of each steer. For
the remainder of each period the amount of feed offered daily to each steer was the
same as that voluntarily consumed on the 10th day. The voluntary feed intake averaged
about 27 of their live weight. Each steer had access. to water and trace mineralized
salt. One of the steers fed flaked (SRC) corn developed a digestive disorder during
the third period and was removed from the experiment.

On the last day of each collection period, samples of rumen ingesta were taken
via fistulae from the ventral sac of the rumen. This was done immediately before
feeding and every two hours thereafter for a period of 10 hours. The pH of the sam-
ples was determined immediately with a Beckman model G pH meter. Bacterial action in
samples was stopped with 10% H2S04 and the samples were stored at OOC until-analyzed.
Before analysis, all samples were strained through four layers of cheesecloth, diluted
to 250 ml. with distilled water and centrifuged at 250 x G.








S- 2-


Following precipitation and filtration of protein from centrifuged rumen fluid,
total VFA were determined by steam..distillation _(Markham, 1942). Analyses for lactic
acid were made by the method of. Barker and Summerson (1941). Individual VFA were mea-
sured by gas-liquid chromatography (GLC) with an F and M Scientific Corporation model
1609 apparatus, provided with a flame ionization detector. A 5 ft. long x 1/4 in.
diameter coiled stainless steel column packed with 10% diethylene glycol adipate and
2% H3P04 on Chromosorb W, 60-80 mesh, was used for the separation of fatty acids.

Water and alcohol soluble carbohydrates were determined in rumen fluid by using
the anthrone reagent as described by Smith et al. (1956).

Diets were analyzed for proximate composition by A.O.A.C. (1960) methods and for
starch content by combining the acid hydrolysis method (A.O.A.C., 1960) with the an-
throne carbohydrate determination (Viles and Silverman, 1949). Gross energy was mea-
sured with a Parr adiabatic oxygen bomb calorimeter. Ground and flaked corn were
analyzed for free sugar content by the method of Clegg (1956) and for starch content
as described above for the whole diets. The solubility of protein fractions of ground
and flaked corn was determined by the method of Nagy et al. (1941).


Results and Discussion

There were no large differences in the ash, ether.extract, crude fiber and gross
energy content of the diets but flaking and pelleted effected differences in the sol-
uble carbohydrate (free sugars and starch) content and the solubility of corn protein
(Table 1).

Soluble carbohydrates in diet. Starch content was highest in SRC and lowest in
HGC-P. The higher starch content of SRC was due to exclusion from the diet of sift-
ings or hominy feed that resulted from cracking and cooling during the process of
flaking. Table 2 shows that the starch content of hominy feed was lower than.that of
ground corn; thus, the increase in starch content of flaked corn was not due to the
flaking process per se but to the removal of the hominy feed portion.

These results differ slightly from those reported by Hastings and Miller (1961)
who found a decrease in the soluble starch and enzyme susceptibility of corn that had
been steam-crimped, a similar process to that used for flaked corn in this study.
They reported that steaming of corn caused a retrogradation of starch during drying.
Their report of a reduction in enzyme susceptibility differed with results reported
by Nasr (1950) who found that amylase enzymes in the rumen attacked more rapidly the
starch granules that had been ruptured during the, process of flaking.

No explanation can be given for the smaller percentage of starch in HGC-P (Table
1) but a similar effect was reported by Hawkins et al. (1963) with pelleted corn and
oats. Adams et al. (1943) reported a decrease:in content of fermentable sugars in
corn that had been heated.

Protein solubility of corn; Results of fractionation.of the total protein in
ground and flaked corn (Tables 2 and 3) showed that the solubility of three of the
protein fractions were smaller in flaked than in ground corn. The ,difference in
solubility of the water, salt and alcohol soluble fractions between HGC and SRC was








- 3 -


54.6, 54.9 and 29.0%, respectively. Only a small change, 1.4%, was noted in the
alkali soluble fraction.

The insoluble protein in ground corn was 10.7% while that in flaked corn was
34.4%. This represents an increase of 69.7% in insolubility of protein caused by
the steaming and rolling of corn. The inclusion of hominy feed would have caused
even lower values in solubility of the protein fractions in flaked corn because the
soluble protein in hominy feed was only 52.7% of the total as compared to 65.6% in
the flaked corn.

Ruminal pH. Results of the rumen metabolism studies are presented in Table 4.
The pH of rumen ingesta taken at two-hr. intervals fluctuated with the concentration
of VFA during a 10-hr. observation period after feeding. There was no appreciable
variation among diets in either range or mean pH. The average pH dropped gradually
from 6.3 6.7 before feeding to 5.0 at six hours after feeding and the lowest values
observed were 4.85 and 4.90. No lactate was found in samples of rumen fluid and no
digestive disorders were observed as reported by Hungate et al. (1952) in animals fed
high starch diets. This apparently indicated an adaptation of the rumen microflora
to,the faster rateof fermentation of the high concentrate diets.

Rumen concentration of total VFA. A considerable increase in VFA concentration
was observed after feeding all diets. Peak concentrations were observed at four hours
after feeding. The lowest VFA concentration was obtained in rumen fluid of steers
fed HGC-P. No significant differences were observed among samples from steers fed
HGC and SRC.

The decreased concentration of VFA with HGC-P suggested a decrease in ruminal
digestion of the pellets. Blaxter and Graham (1956) found that pelleted high rough-
age diets had a faster rate of,passage than the same diet fed in ground form. Al-
though concentrates have a different physical pathway than roughages during their
digestion in the rumen (Smith et al., 1956), it is possible that pelleting of a high
concentrate diet may cause a faster rate of passage through the ruminoreticulum
(Campling et al. Cited by Bath and Rook, 1963). VFA utilization by the ruminant has
been found to be an inefficient process due to the high amounts of energy lost as
heat increment (Armstrong and Blaxter, 1957 a,b and Armstrong et al., 1958). If the
pelleted feed stayed a shorter time in the rumen, a larger portion of the soluble
nutrients in the pellets may have passed to the lower digestive tract for more effi-
cient digestion and utilization. This may explain the more efficient gains made by
fattening steers fed the pelleted diet in feedlot performance experiments reported
by Cabezas et al. (1964).

Molar proportions of rumen VFA. Table 4 shows that the molar proportion of
acetate was lowest and propionate highest when SRC was fed. This produced a signifi-
cant decrease in the acetate to propionate ratio as compared to HGC and HGC-P. The
widest ratio was observed for HGC-P due to the relatively low propionate proportion.

These results show that flaking of corn lowers the relative acetate and raises
the relative propionate concentrations in the rumen. This is in agreement with find-
ings by Phillipson (1952), Balch et al. (1955), Balch and Rowland (1957), Ensob-et
al. (1959) and Newland et al. (1962). These studies indicate that flaking of corn
is a major method of altering volatile fatty acid production in the rumen and this








-4-


may account for the increased efficiency of gain observed with SRC in feedlot experi-
ments reported by Cabezas et al. (1964).

Results obtained with HGC-P differ with those obtained by Rhodes and Woods (1962)
who found an increase in ruminal propionate in lambs fed a pelleted diet containing
53% ground corn, 33% ground alfalfa hay and 14% supplement. The difference appears
to be in the corn to roughage ratios between diets. Shaw et al. (1960) found that the
inclusion of pelleted alfalfa hay in a corn to hay ratio similar to that used by Rhodes
and Woods (1962), resulted in a greater increase in propionate concentration in the
rumen than when ground corn was fed alone or with ground alfalfa hay. The amounts of
dehydrated alfalfa meal used in this study, 5%, apparently were too low to cause the
type of rumen fermentation reported by Rhodes and Woods (1962). Thus, the increase in
feed efficiency previously obtained by Cabezas et al. (1964) withthe HGC-P apparently
was not due to an altered acetate to propionate ratio. It is possible that a faster
rate of passage of HGC-P permitted a more efficient utilization of the unfermented nu-
trients in the lower digestive tract.

During the 10-hr. sampling period a fall in pH and a rise in total VFA was invari-
ably accompanied by a decrease in acetate to propionate ratio in the rumen. Similar
changes in the composition of a mixture of ruminal acids were reported by Gray and Pil-
grim (1951) in sheep fed wheaten hay and lucerne hay, by Rhodes and Woods (1962) in
sheep fed pelleted high concentrate diets and by Bath and Rook (1963) with a variety
of diets and feeding regimes. Shaw (1961) reported that variations in molar propor-
tions of individual volatile fatty acids throughout a feeding cycle are, in general,
small. He stated that a single sample drawn at any time throughout a feeding cycle
is usually adequate to characterize a diet. In this study where feed was offered once
daily the extreme values observed during the 10-hr. sampling period for acetate to pro-
pionate ratio in rumen fluid from steers fed HGC, SRC and HGC-P respectively were:
2.44 to 1.44, 1.89 to 1.15 and 2.47 to 1.70. These differences due to time interval
variation with different physical forms of a diet indicate the desirability of sampling
several times after a single feeding.

Water soluble carbohydrates in the rumen. Table 4 shows the concentrations of
water soluble carbohydrates in rumen ingesta at different times after feeding.

No significant differences were obtained between treatments; however, Figure 1
shows that each of the diets produced a different concentration of water soluble carbo-
hydrates in the rumen. SRC produced the highest concentration at two hours after
feeding. Although this diet had the highest soluble carbohydrate content the differ-
ence in rumen fluid concentration appeared to be of greater magnitude. While the water
soluble carbohydrates in the rumen of steers fed SRC and HGC-P had decreased sharply
at four hours after feeding, the concnetration in rumens of steers fed HGC stayed at
approximately the same level for another four hours then decreased. These results sug-
gest a faster rate of dissimilation or passage of carbohydrates in SRC and HGC-P than
HGC. Salsbury et al. (1961) has reported that moist heated corn was digested more
rapidly by rumen microorganisms.in vitro.

Alcohol soluble carbohydrates in the rumen. Figure 2 shows the changes in alco-
hol soluble carbohydrates in the rumen as influenced by diet. They represent the sim-
ple sugars resulting from microbial dissimilation of water soluble carbohydrates. -In








- 5 -


steers fed HGC and SRC, the concentrations of alcohol soluble carbohydrates in samples
of rumen ingesta had similar patterns to those of the water soluble carbohydrates. In
steers fed SRC, the alcohol soluble carbohydrate content was highest at two hours after
feeding then decreased sharply indicating a rapid fermentation of the sugars by rumen
microorganisms. This was associated with an increase in propionate which probably re-
sulted from the production of higher amounts of lactate than in the other two diets
(Reid et al., 1957). The fact that lactate was not found in rumen fluid samples, as
it was by Phillipson (1952) and Balch and Rowland (1957) with diets containing flaked
corn, was probably due to the long period of adaptation allowed for development of
microbial populations in which lactate utilization equalled production.

In steers fed HGC, slower fermentation of the alcohol soluble or free sugars was
associated with a slower dissimilation of water soluble carbohydrates. This is a fur-
ther indication of the difference in the nature of the carbohydrates between HGC and
SRC.

In steers fed HGC-P, different results were obtained. In addition to having a
lower concentration of ruminal alcohol soluble carbohydrates than in steers fed HGC or
SRC, differences were observed during the sampling period. The peak concentration of
alcohol soluble carbohydrates was at two hours after feeding as in the other diets but
the increase was not relative to the increase of water soluble carbohydrates. The
decrease in concentration after two hours was not as sharp as in steers fed SRC. This
observation of HGC-P could have indicated a rapid digestion of carbohydrates by the
rumen microorganisms but that would have resulted in a higher propionate concentration
than in steers fed HGC which was not the case. Therefore, a faster rate of passage
of HGC-P through the rumen resulting in a lower supply of carbohydrates to the rumen
microorganisms is apparent. This explanation is strengthened by the lower VFA levels
found in the rumen and the more efficient utilization of the diet by steers fed the
pelleted diet.


Summary

Fistulated beef steers were used to measure effects of a high concentrate (72%
shelled corn) diet in three physical forms on ruminal pH, concentration of total vola-
tile fatty acids.(VFA),.molar proportions of VFA and concentrations of soluble carbo-
hydrates. Treatments were diet containing hammermill-ground corn (HGC), HGC diet
pelleted (HGC-P) and diet containing flaked or steamed rolled cracked corn (SRC).

Starch content of SRC was highest, 55% compared to 51.3% for HGC and 48.1% for
HGC-P. Removal of hominy meal in flaking process largely accounted for high starch
content of SRC. Starch content of ground shelled corn, flaked corn and hominy meal
was 71.7%; 76.4 and 49.3% respectively.

Water, salt and alcohol soluble fractions of protein in flaked corn were less
soluble than in ground corn by 54.6, 54.9 and 29.0% respectively. Insoluble protein
content of flaked corn was 34.4% compared to 10.7% for ground shelled corn.

The average pH of rumen fluid from steers fed all diets dropped from 6.3 6.7
before feeding to 5.0 at six hours after feeding. Rumen lactate and digestive dis-
orders were not found.








- 6 -


Peak concentrations of total VFA in rumen fluid occurred four hours after
feeding of each diet. HGC-P produced lowest total VFA concentration, 13.5 meq./100 gm.
compared to 15.5 for HGC and 15.1 for SRC.

Acetate to propionate ratio in rumen fluid was narrowest in steers fed SRC and
widest in steers fed HGC-P at each sampling time interval after feeding.

Both water and alcohol soluble carbohydrate concentrations in rumen fluid were
highest at two hours after feeding of each diet, were relatively higher at two-hr.
sampling time in steers fed SRC and showed fastest rate of decrease in concentration
after the two-hr. sampling in SRC-fed steers. These observations partially explain
the previously reported superiority of feed conversion by steers fed SRC and HGC-P
diets.




Literature Cited

1. Adams, S. L., W. H. Stark, and P. Kolochov. 1943. Reduction of the fermentable
carbohydrate content of corn by kiln drying. Cereal Chem. 20:260.

2. Armstrong, D. G., and K. L. Blaxter. 1957a. The heat increment of steam-volatile
fatty acids in fasting sheep. Brit. J. Nutr. 11:247.

3. Armstrong, D. G., and K. L. Blaxter. 1957b. The utilization of acetic, propionic
and butyric acids by fattening sheep. Brit. J. Nutr. 11:413.

4. Armstrong, D. G., K. L. Blaxter and N. McC. Graham and F. W. Wainman. 1958. The
utilization of the energy of two mixtures of steam-volatile fatty acids by
fattening sheep. Brit. J. Nutr. 12:177.

5. A.O.A.C. 1960. Methods of Analysis. 9th ed. Association of Official Agricul-
tural Chemists. Washington, D. C.

6. Balch, C. C., D. A. Balch, S. Bartlet, Z. D. Hosking, V. W. Johnson, S. J. Rowland
and J. Turner. 1955. Studies of the secretion of milk of low fat content by
cows on diets low in hay and high in concentrates. V. The importance of the
type of concentrate. J. Dairy Res. 22:10.

7. Balch, C. C. and S. J. Rowland. 1957. Volatile fatty acids and lactic acid in
the rumen of dairy cows receiving a variety of diets. Brit. J. Nutr. 11:238.

8. Barker, S. B. and W. H. Summerson. 1941. The colorimetric determination of lac-
tic acid in biological materials. J. Biol. Chem. 138:535.

9. Bath, I. H. and J. A. F. Rook. 1963. 'The evaluation of cattle foods and diets
in terms of ruminal concentration of volatile fatty acids. I. The effect of
intake, frequency of feeding, the ratio of hay to concentrates in the diet
and of supplementary feeds. J. Agr. Sci. 61:341.







- 7. -


10. Blaxter, K. L. and N. McC. Graham. 1956. The effect of the grinding and cubing
process on the utilization of energy of dried grass. J. Agr. Sci. 47:207.

11. Cabezas, M. T. 1964. The effect of physical form on nutritive value of ruminant
diets. Ph.D. Dissertation. University of Florida.

12. Clegg, K. M. 1956. The application of flu anthrone reagent to the estimation of
starch in cereals. J. Sci. Food Agr. 7:40.

13. Ensor, W. L., J. C. Shaw and H. F. Tellechea. 1959. Special diets for the pro-
duction of low fat milk and more efficient gains in body weight. J. Dairy
Sci. 42:189.

14. Gray, F. V. and A. F. Pilgrim. 1951. Fermentation in the rumen of the sheep.
II. The production and absorption of volatile fatty acids during the fermen-
tation of wheaten hay and lucerne hay in the rumen. :J. Exp. Biol. 28:83.

15. Hastings, W. H. and G. D. Miller. 1961. Biochemical changes in grains. Cereal
Sci. Today. 6:6.

16. Hawkins, G. E., G. E. Paar and J. E. Little. 1963. Physiological responses of
lactating dairy cattle to pelleted corn and oats. J. Dairy Sci. 46:1073.

17. Hungate, R. E., R. W. Dougherty, M. P. Bryant and R. M. Cello. 1952. Microbio-
logical and physiological changes associated with acute indigestion in sheep.
Cornell Vet. 42:423.

18. Markman, R. 1942. A steam distillation apparatus suitable for micro-Kjeldahl
analysis. Biochem. J. 36:790.

19. Nagy, D., W. Weidlein and R. H. Hixon. 1941. Factors affecting the solubility
of corn proteins. Cereal Chem. 18:514.

20. Nasr, H. 1950. Amylolytic activity in the rumen of the sheep. J. Agr. Sci.
40:308.

21. Newland, H. W., W. T. Magee, G. A. Branaman and L. H. Blakeslee. 1962. Effect
of heat-processing and pelleting corn for steers and lambs. J. Animal Sci.
21:711.

22. Phillipson, A. T. 1952. The fatty acids present in the rumen of lambs fed on
a flaked maize ration. Brit. J. Nutr. 6:190.

23. Reid, R. L., J. P. Hogan and P. K. Briggs. 1957. The effect of diet on indi-
vidual volatile fatty acids in the rumen of sheep, with particular reference
to the effect of low rumen pH and adaptation on high starch diets. Australian
J. Agr. Res. 8:691.

24. Rhodes, R. W. and W. Woods. 1962. Volatile fatty acid measurements on the rumen
contents of lambs fed rations of various physical forms. J. Animal Sci.
21:483.







-8-

25. Salsbury, R. L., J. A. Hoefer and R. W. Luecke.- 1961. Effect of heating starch
on its digestion by rumen microorganisms.' J. Animal Sci. 20:569.

26. Shaw, J. C., W. L. Ensor, H. F. Tellechea and S. D. Lee. 1960. Relation of
diet to rumen volatile fatty acids, digestibility, efficiency of gain and
degree of unsaturation of body fat in steers. J. Nutr. 71:203.

27. Shaw, J. C. 1961. Nutritional physiology of the rumen. Proc. 8th Int. Cong.
Animal Prod., p. 29.

28. Smith, P. H., H. C. Sweeney, J. R. Rooney, K. W. King and W. E. C. Moore. 1956.
Stratifications and kinetic changes in the ingesta of the bovine rumen. J.
Dairy Sci. 39:598.

29. Viles, F. J., Jr., and L. Silverman. 1949. Determination of starch and cellu-
lose with anthrone. Anal. Chem. 21:950,








- 9 -


TABLE 1.

INGREDIENTS AND PROXIMATE ANALYSIS OF EXPERIMENTAL DIETS


Method of processing corn
Ground Flaked Pelleteda

HGC SRC HGC-P


Ingredients, %
Corn, yellow 72.0 72.0 72.0
Soybean oil meal, 44% 2.5 2.5 2.5
Cottonseed meal, 41% 2.5 2.5 2.5
Urea, 262% 1.0 1.0 1.0
Cane molasses, std. 5.0 5.0 5.0
Alfalfa meal, dehyd. b 5.0 5.0 5.0
Mineral-ahd Vitamin mix .2.0 2.0 2.0
Corn cobs, ground 10.0 10.0 10.0
Proximate analysis
Nitrogen, % 2.5 2.4 2.6
Ash, % 7.2 7.2 7.2
Ether extract, % 4.0 4.0 3.9
Crude fiber, % 5.9 : 5.7 5.8
Starch, % 51.3 55.0 48.1
Gross energy, kcal./gm. 4.3 4.3 4.2



a Whole diet was pelleted.

b Mineral mix contained 30% sodium chloride, 1.4% iron, 0.108% copper,
0.10% cobalt, 18.9% calcium, 5.5% phosphorus, 0.485% manganese and
0.011% iodine. Vitamin mix contained 10,000 I.U. vitamin D2 per lb.
and was adjusted to provide an average intake of 20,000 I.U. vitamin A
per day.


c Moisture-free basis.









- 10 -


TABLE 2

EFFECT OF FLAKING ON SOLUBLE CARBOHYDRATE
AND SOLUBLE PROTEIN CONTENT OF CORN


Ground corn
HGC


Flaked corn
SRC


.Hominy. feed


% % %

Soluble carbohydrates 73.3 78.0 53.3
Free sugars 1.6 1.6 4.0
Starch 71.7 76.4 49.3
Soluble protein 10.0 6.1 11.8
Water soluble 1.6 0.6 3.5
Salt soluble 0.8 0.3 1.8
Alcohol soluble 5.1 3.0 2.6
Alkali soluble 2.5 2.2 3.9
Insoluble protein 1.2 3.2 10.6

a
b Siftings from cracking that were not included in the diet.
Moisture-free basis.




TABLE 3

SOLUBILITY OF PROTEIN FRACTIONS IN GROUND AND FLAKED CORN



Ground corn Flaked corn % Change



Soluble fractions, %
Water 14.3 6.5 54.6
Salt 7.1 3.2 54.9
Alcohol 45.5 32.3 29.0
Alkali 22.3 23.7 1.4
Insoluble fraction 10.7 34.4 69.7


___ ___
__







TABLE 4


EFFECT OF PHYSICAL FORM OF DIET ON VOLATILE FATTY ACID CONTENT OF RUMEN INGESTA
COLLECTED FROM FISTULATED STEERS AT DIFFERENT INTERVALS OF TIME AFTER FEEDING


Soluble carbohydrates
Diet and Rumen Total VFA Molar % of total VFA C2/C3 Water Alcohol
Collection time pH meq./100 gm. C2 C3 C4 iso-c5 C5 ratio mg./l0 ml. mg./100 ml.



Ground
a
8:00 a.m. 6.4 6.91 62.70 25.87 6.72 3.49 1.22 2.42 707 597
10:00 a.m. 5.6 13.43 56.94 31.78 7.35 1.96 1.97 1.79 1359 1145
12:00 5.1 15.49 54.84 32.35 9.32 1.69 1.80 1.70 1273 1179
2:00 p.m. 5.0 14.38 53.51 32.86 10.06 1.90 1.67 1.63 1300 1193
4:00 p.m. 5.0 13.09 51.57 34.20 10.73 1.70 1.80 1.51 1216 958
6:00 p.m. 5.3 11.66 50.94 35.37 10.49 1.51 1.69 1.44 315 760
Flaked
8:00 a.m. 6.3 7.97 57.08 30.27 7.43 4.32 0.90 1.89 718 677
10:00 a.m. 5.6 14.20 55.15 33.70 6.97 2.88 1.30 1.64 2324 1712
12:00 5.1 15.06 51.52 35.15 7.92 2.77 1.64 1.43 1533 1454
2:00 p.m. 5.0 14.78 49.97 38.42 8.16 2.04 1.41 1.30 1203 1032
4:00 p.m. 5.1 12.01 46.78 40.55 8.87 1.84 1.96 1.15 1559 966
6:00 p.m. 5.4 10.86 47.97 38.42 9.11 2.09 2.41 1.25 1125 1062
Pelletedb
3:00 a.m. 6.7 6.19 61.91 25.05 7.08 4.45 1.51 2.47 818 591
10:00 a.m. 5.5 12.52 58.42 26.78 10.19 2.51 2.10 2.18 1668 1128
12:00 5.1 13.53 56.39 28.66 10.99 1.80 2.16 1.97 1130 967
2:00 p.m. 5.0 13.30 56.34 27.79 11.90 2.00 1.97 2.03 1132 881
4:00 p.m. 5.1 12.13 52.23 30.73 12.69 2.30 2.05 1.70 1041 840
6:00 p.m. 5.4 9.73 54.35 29.93 11.03 2.68 2.01 1.82 925 761


SFeedin time fnr all treatments was R: O a.m.


Whole diet was pelleted.


U _Y__Y







- 12 -


2400


2200


2000


/ \


I


r 1400 / \


1200 -


S l3oo 1/"
o /
800 0 i


600-


400 -
--- Diet containing ground corn

200[ --- Diet containing flaked corn
Pelleted diet
0 ------.-
2 4 6 3 10

Hours After Feeding


Figure 1. Changes in the Water Soluble Carbohydrate Content
of Rumen Ingesta in Steers Fed Diets in Different
Physical Forms




. I


- 13 -


2400


2200




20000 -

1300-


160 -


I

/

- I


- Diet containing ground corn
Diet containing flaked corn
S- Pelleted diet


Hours After Feeding


Figure 2.


Changes in the Alcohol Soluble Carbohydrate Content
of Rumen Ingesta of Steers Fed Diets in Different
Physical Forms


JFH:jw
500 copies
An.Sci.


14f00


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800


600


200
200 -


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